EP0549221A1 - Commutateurs et capteurs utilisant des contacts obtenus par pultrusion - Google Patents
Commutateurs et capteurs utilisant des contacts obtenus par pultrusion Download PDFInfo
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- EP0549221A1 EP0549221A1 EP19920311374 EP92311374A EP0549221A1 EP 0549221 A1 EP0549221 A1 EP 0549221A1 EP 19920311374 EP19920311374 EP 19920311374 EP 92311374 A EP92311374 A EP 92311374A EP 0549221 A1 EP0549221 A1 EP 0549221A1
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- Prior art keywords
- contact
- pultrusion
- fibers
- electronic
- contacts
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H1/00—Contacts
- H01H1/06—Contacts characterised by the shape or structure of the contact-making surface, e.g. grooved
Definitions
- This invention relates to improvements in electronic sensors and switches, and, more particularly, to improvements in switch and sensor designs employing pultruded contact members.
- the invention also relates to a sensor using pultruded contact members to determine the presence of an object such as a sheet of paper in a detection zone.
- switches employ a movable member that carries a conductor in a manner such that it can be selectively brought into electrical contact with another conductor.
- most sensors employ two members having conductors in electrical contact, wherein the electrical contact is interrupted by the object to be sensed as the object passes between the members.
- the conductors are generally metal, but other conducive materials have been used as well.
- a photoconductive insulating surface often in the form of a moving belt, is uniformly charged and exposed to a light image from an original document.
- the light image causes the exposed or background areas to become discharged, and creates an electrostatic latent image on the surface corresponding to the image contained within the original document.
- a light beam such as a laser beam may be modulated and used to selectively discharge portions of the photoconductive surface to record the desired information thereon.
- the electrostatic latent image is made visible by developing the image with a developer powder, referred to in the art as toner, which may be subsequently transferred to a support surface such as paper to which it may be permanently affixed by the application of heat and/or pressure.
- switches or sensors are provided to detect the presence of the paper as it is moved through the various processing stages of the machine.
- the detecting switches and sensors need to be made sturdy and reliable, adding to the complexity and expense of the machine.
- US-A-4,641,949 describes the application of carbon fibers combined to form the basis of a non-metallic contact which in turn is the basis of a paper sensor.
- a switch having two electronic contacts.
- One of the electronic contacts includes a pultrusion having a plurality of electrically conductive fibers carried by a host material.
- One end of the pultrusion has a fibrillated end portion to provide the electronic contact.
- one of the electronic contacts is movable into and out of electrical connection with another of the contacts.
- the host material can be (1) a polyimide composition, (2) a polymer from the group consisting of low molecular weight polyethylene, polypropylene, polystyrene, polyvinylchloride, or (3) a composition that volatilizes rapidly and cleanly upon direct exposure to a laser beam of predetermined energy, and the continuous strand fibers can be carbon fibers.
- the present invention further provides an electronic switch according to claim 4 of the appended claims.
- a switch which has first, second, and third electronic contacts.
- a fourth electronic contact is formed of a pultrusion including a plurality of electrically conductive fibers and a host material carrying the plurality of fibers, one end of the pultrusion having a fibrillated end portion, which can be fan shaped, that is selectively movable (rotatable) to contact either the first and second electronic contacts or the second and third electrical contacts.
- the present invention further provides a switch according to claim 5 of the appended claims.
- a switch which has first and second pultrusions, at least one of which can be cylindrically shaped, each comprising a plurality of electrically conductive fibers and a host material carrying the plurality of fibers.
- One end of the pultrusion has a fibrillated end portion that presents a plurality of electrically conductive fibers that are arranged in the host material to be present only in selected areas at the fibrillated end portion.
- the first and second pultrusions are arranged in end to end relationship, and at least one of the first and second pultrusions is rotatable to selectively establish electrical connection between the electrically conductive fibers of the first and second pultrusions.
- the present invention further provides a switch according to claim 6 of the appended claims.
- a switch which has a selectively rotatable insulating substrate that has a conductive portion thereon.
- First and second pultrusions each comprising a plurality of electrically conductive fibers and a host material carrying the plurality of fibers, are provided, one end of each of the pultrusion having a fibrillated end portion.
- the first and second pultrusions being arranged with the fibrillated end portions in contact with the substrate, whereby when the substrate is rotated, the conductive portion is brought into electrical contact with the fibrillated end portions of the pultrusions.
- the fibrillated end portions of the first and second pultrusions are in contact with a face of the substrate along an axis parallel to an axis of rotation of the substrate, and in another embodiment, the substrate is disk shaped, and the fibrillated end portions of the first and second pultrusions are in contact with the substrate from an edge and along an axis perpendicular to an axis of rotation of the substrate.
- the substrate may be circular, and said conductive portion may extend over a semicircular portion of said substrate.
- the present invention further provides a switch according to claim 7 of the appended claims.
- a switch in this aspect of the invention, has first and second pultrusions, each comprising a plurality of electrically conductive fibers and a host material carrying the plurality of fibers with one end of the pultrusion being fibrillated.
- An electrical contact is provided that is selectively movable into and out of contact with the fibrillated end portions of the first and second pultrusions.
- An arm may be provided to carry the electrical contact. The arm may be rotatably mounted to enable the electrical contact to be selectively movable into and out of contact with the fibrillated end portions of the first and second pultrusions.
- the present invention further provides a sensor according to claim 6 of the appended claims.
- a sensor for detecting the presence of an article in a detection zone.
- the sensor includes a contact at one side of the detection zone, and a pultrusion including a plurality of electrically conductive fibers and a host material carrying the plurality of fibers, supported at another end of the detection zone.
- One end of the pultrusion has a fibrillated end portion with conductive fibers of the pultrusion extending across the detection zone in electrical connection with the contact. The fibers are displaced by the article when the article is present in the detection zone to disconnect the electrical connection.
- the sensor is particularly well adapted to sense a sheet of paper or the like, for example, in an electrostatographic reproducing machine.
- the sensor contact may be connected to a source of electrical potential and said conductive fibers of said pultrusion are connected to a reference potential, and when said sheet of paper is transported through said detection zone, said conductive fibers serve to establish the reference potential on said sheet of paper.
- the reference potential is preferably ground, and when said sheet of paper is transported through said detection zone, said conductive fibers serve to discharge any static charges existing on said sheet of paper.
- the sensor may further comprise a second contact at said one side of said detection zone, said fibrillated end portion extending across said detection zone being in electrical connection with said first mentioned and said second contacts, completing an electrical flow path therebetween, so that when said article is transported through said detection zone, said fibrillated end portion is displaced by said article to interrupt said electrical flow path.
- the paper detection zone is elongated in one direction transverse to a direction in which said sheet of paper traverses said paper detection zone, and said pultrusion is elongated to extend along said direction.
- Figure 1 is a side elevation view of an embodiment of a switch using a rotating pultruded member.
- Figure 2 is a side elevation view of another embodiment of a switch utilizing semicircular shaped pultruded members.
- Figure 3 is end elevation view of the switch of Figure 2 taken at 3-3.
- Figure 4 is a side elevation of a single pole single throw switch using pultruded contact members for contacting a rotary disc contact.
- Figure 5 is a top cutaway view taken at 5-5 in Figure 4.
- Figure 6 is and enlarged top elevation view of a portion of the switch of Figure 4 illustrating the contact between the segmented disc and pultruded sleeve contact.
- Figure 7 is a front elevation view of another switch embodiment, in accordance with the invention, in which a contact plate is moveable brought into contact with a plurality of pultruded contact members.
- FIG. 8 is a schematic diagram of an electrical circuit in which a switch fabricated in accordance with the principles of the present invention is employed.
- Figure 9 is a side elevation view of a switch or sensor for sensing the presence of a sheet of paper or the like, in accordance with another preferred embodiment of the invention, including an electrical schematic diagram of an active chip level interfacing circuit for use therewith.
- Figure 10 is a side elevation view of another embodiment of a switch or sensor for sensing the presence of a sheet of paper or the like.
- Figure 11 is a perspective view of another embodiment of a switch or sensor for sensing the presence of a sheet of paper which serves also to establish a charge on the paper or to eliminate any static charges on the paper.
- Figure 12 is an exemplary functional schematic of the active interface circuit of Figs. 8 and 9.
- Figure 13 is an exemplary circuit schematic of the active interface circuit.
- Figure 14 is a graph illustrating the output waveform of fibers falling on an opposing contact without an active interface circuit.
- Figure 15 is a graph illustrating the output waveform with the active interface circuit in place.
- an electronic component is provided and a variety of electronic devices for conducting electrical current such as switches, sensors, etc. are provided which are of greatly improved reliability, are of low cost and easily manufacturable and are capable of reliably operating in low energy circuits.
- these devices are low energy devices, using low voltages within the range of millivolts to hundreds of volts and currents within the range of microamps to hundreds of milliamps as opposed to power applications of tens to hundreds of amperes, for example.
- the present invention may be used in certain applications in the single amp region it is noted that best results are obtained in high resistance circuitry where power losses can be tolerated.
- these devices may be used in certain applications in the high voltage region in excess of 10,000 volts, for example, where excessive heat is not generated.
- These devices are generally electronic in nature within the generic field of electrical devices meaning that their principle applications are in signal level circuits although as previously stated they may be used in certain low power applications where their inherent power losses may be tolerated.
- an electronic component is made from a pultruded composite member having a fibrillated brush-like structure at one end which provides a densely distributed filament contact with another component.
- densely distributed filament contact it is intended to define an extremely high level of contact redundancy insuring electrical contact with another contact surface in that the contacting component has in excess of 1000 individual conductive fibers per square millimeter.
- a pultrusion of the type having a plurality of conductive fibers carried within a host matrix (sometimes referred to as a distributed fiber pultrusion) serving as switch contacts is advanced.
- Switches and sensors employing this feature can be fabricated at very low cost, and, due to the inertness and reliability of the distributed fiber pultrusion contact, many new electronic device configurations which would have earlier been judged to be unreliable due to the application of metal contacts in open air can be enabled.
- a pultruded carbon material can be used as both a connector pin and an element of a switch, it becomes apparent that miniature switches and sensors could be built, for example, into connector headers.
- the Molex 0.025 inch square (635 ⁇ m square) pin and headers are examples of the configurations which are easily transformed by the distributed fiber contact materials into small, inexpensive switches and sensors.
- One overriding consideration is enabling the ability to manufacture miniature sensors and switches for virtually pennies, with high performance of the carbon fiber and carbon fiber pultrusion composites.
- Such sensors and switches can serve a variety of applications within a xerographic engine and its peripherals, all enabled by pultrusion carbon fiber rods which are ordinarily rigid but through laser heating can expose conductive parts that are flexible and can be easily contacted for electrical connections, as below described in detail.
- an improved electrical contact device is provided that is of improved reliability, is of low cost and is easily manufacturable.
- a manufacturing process known generally as a pultrusion process, with the fibrillation of at least one end of the pultrusion.
- One pultrusion composition that can be employed in practicing this invention is of the type that comprises continuous fibers or strands of resistive carbon fiber filler within a host polymer.
- Such carbon fiber pultrusions are a subcategory of high performance conductive composite plastics, and comprise one or more types of continuous, conductive reinforcing filaments in a binder polymer. They provide a convenient way to handle, process and use fine diameter, carbon fibers without the problems typically encountered with free conductive fibers.
- the pultrusion process generally consists of pulling continuous lengths of fibers first through a resin bath or impregnator, then into a preforming fixture where the resulting section is at least partially shaped and excess resin and/or air are removed. The section is then pulled into heated dies where it is continuously cured.
- conductive carbon fibers are submersed in a polymer bath and drawn through a die opening of suitable shape at high temperature to produce a solid piece having dimensions and shapes of that of the die.
- the solid piece can then be cut, shaped, or machined.
- a structure can be achieved that has thousands of conductive fiber elements contained within the polymer matrix, the ends of the fiber elements being exposed to provide electrical contacts.
- the very large redundancy and availability of electrical contacts enables a substantial improvement in the reliability of these devices.
- the shaped member can be formed with the fibers being continuous from one end of the member to the other. Accordingly, the pultruded composite may be formed in a continuous length during the pultrusion process, then cut to any suitable dimension, with a very large number of potential electrical contacts provided at each end. Such pultruded composite members may have either one or both of its ends subsequently fibrillated.
- any suitable fiber having a high resistivity may be used in the practice of the invention.
- the conductive fibers are nonmetallic and have a DC volume resistivity of from about 1 x 10 ⁇ 5 to about 1 x 1010 ohm-cm and preferably from about 1 x 10 ⁇ 4 to about 10 ohm-cm to minimize resistance losses and suppress RFI.
- the upper range of resistivities of up to 1 x 1010 ohm-cm. could be used, for example, in those special applications involving extremely high fiber densities where the individual fibers act as individual resistors in parallel thereby lowering the overall resistance of the pultruded member enabling current conduction.
- nonmetallic is used to distinguish from conventional metal fibers which exhibit metallic conductivity having resistivity of the order of 1 x 10 ⁇ 6 ohm-cm and to define a class of fibers which are nonmetallic but can be treated in ways to approach or provide metal like properties. Higher resistivity materials may be used if the input impedance of the associated electronic circuit is sufficiently high.
- carbon fibers are particularly well suited as preferred filler because they are chemically and environmentally inert, possess high strength and stiffness, can be tailored to virtually any desired resistivity, and exhibit a negative coefficient of thermal resistivity.
- the individual conductive fibers can be made circular in cross section with a diameter generally in the order of from about 4 micrometers to about 50 and preferably from about 7 micrometers to 10 micrometers. This provides a very high degree of redundancy in a small cross sectional area.
- the fibers provide a multiple redundancy of contact points, for example, in the range between about 0.05X105 and 5X105 contacts/cm2, preferably about .05580 contacts/cm2. This is believed to enable ultrahigh contact reliability.
- such fibers are also are likely to minimize harmful contamination within the machines.
- the fibers are typically flexible and compatible with the polymer systems within which they are carried.
- Typical fibers may include carbon, carbon/graphite, metalized or metal coated carbon fibers and metal coated glass fibers.
- a particularly preferred class of fibers that may be used are those fibers that are obtained from controlled heat treatment processing to yield complete or partial carbonization of polyacrylonitrile (PAN) precursor fibers. It has been found for such fibers that by carefully controlling the temperature of carbonization within certain limits that precise electrical resistivities for the carbonized carbon fibers may be obtained.
- PAN polyacrylonitrile
- the carbon fibers from polyacrylonitrile (PAN) precursor fibers are commercially produced by the Stackpole Company, Celion Carbon Fibers, Inc., division of BASF and others in yarn bundles of 1,000 to 160,000 filaments.
- the yarn bundles are carbonized in a two-stage process.
- the first stage involves stabilizing the PAN fibers at temperatures of the order of 300°C in an oxygen atmosphere to produce preox-stabilized PAN fibers.
- the second stage involves carbonization of the fibers at elevated temperatures in an inert atmosphere, such as an atmosphere containing nitrogen.
- the DC electrical resistivity of the resulting fibers is controlled by the selection of the temperature of carbonization. For example, carbon fibers having an electrical resistivity of from about 102 to about 106 ohms-cm are obtained if the carbonization temperature is controlled in the range of from about 500°C to 750°C while carbon fibers having D.C.
- resistivities of 10 ⁇ 2 to about 10 ⁇ 6 ohm-cm result from treatment temperatures of 1800 to 2000°C.
- carbon fibers having an electrical resistivity of from about 106 ⁇ cm to 1010 ⁇ cm are obtained if the carbonization temperature is controlled in the range of from about 750°C to about 1150°C.
- U.S. Patent 4,761,709 to Ewing et al attention is directed to U.S. Patent 4,761,709 to Ewing et al and the literature sources cited therein at column 8.
- these carbon fibers have a modulus of from about 30 million to 60 million psi or 205 - 411 GPa which is higher than most steels thereby enabling a very strong pultruded composite member.
- the high temperature conversion of the polyacrylonitrile fibers results in a fiber which is about 99.99% elemental carbon which is inert and will resist oxidation.
- conductive carbon fibers have a negative coefficient of thermal conductivity so that as the individual fibers become hotter with the passage of, for example, a spurious high current surge, they become more conductive. This provides an advantage over metal contacts since metals operate in just the opposite manner and therefore metal contacts tend to burn out or self destruct.
- the carbon fibers have the further advantage in that their surfaces are inherently rough and porous thereby providing better adhesion to the polymer matrix.
- the inertness of the carbon material yields a contact surface relatively immune to contaminants of the plated metal.
- the carbon fibers are enclosed in any suitable polymer matrix.
- the polymer matrix should be of a resin binder material that will volatilize rapidly and cleanly upon direct exposure to the laser beam during laser processing below described.
- Polymers such as low molecular weight polyethylene, polypropylene, polystyrene, polyvinylchloride, and polyurethane may be particularly advantageously employed.
- Polyesters, epoxies, vinyl esters, polyetheretherketones, polyetherimides, polyethersulphones and nylon are in general, suitable materials with the polyesters and vinylesters being preferred due to their short cure time, relative chemical inertness and suitability for laser processing.
- a laser (not shown) can be used to both cut individual components for use as an electrical switch or sensor contact.
- a focused laser can be used to cut the pultrusion and simultaneously volatilize the binder resin in a controlled manner a sufficient distance back from the cut to produce in one step a distributed filament contact.
- the length of exposed carbon fiber can be controlled by the laser power and cut rate.
- Various tip shapes can be achieved by changing the laser incidence angle.
- a suitable protrusion can be cut by laser techniques to form a contact of desired length from the longer pultrusion length, and both severed ends can be fibrillated to provide a high redundancy fiber contact member downstream for contact to electrical circuitry to be switched, and a high redundancy fiber contact upstream to contact a switch or sensor contact plate.
- Any suitable laser can be used which will be absorbed by the matrix of the host polymer, so that the host polymer will be volatilized.
- Specific lasers which may be used include a carbon dioxide laser, the YAG laser, or the argon ion laser.
- the carbon dioxide laser mentioned is particularly suited for this application, however, since it is the most reliable, best suited for polymer matrix absorption, and is most economical in manufacturing environments.
- a switch embodiment 10 in accordance with a preferred embodiment of the invention, can be formed entirely of carbon fiber pultrusions 11, 12, and 13, or alternatively, a square carbon fiber pultrusion, for instance, of 0.025 inch (635 ⁇ m) on a side may be used.
- the pultrusions 11, 12, and 13 are pressed onto metal pins 16, 17, and 18, respectively, and mating contact is by the fibrillated carbon fiber ends 20, 21, and 22 to take up mounting tolerances.
- Three rods 16, 17, and 18 are shown, for example, which are to be interconnected in a desired combination.
- the top rod 16 serves as a normally closed contact rod and the center rod 17 serves as a common line contact rod.
- the pultrusions 11 and 12 of the top and center pins 16 and 17 are connected together by a contact or wiper assembly 25 formed of a pultrusion 26 of electrically conducting fibers 27 that have been fibrillated along a surface to form a fan shaped conductive portion having a circumference sufficient to encompass the two spaced contact rods 16 and 17.
- the wedge shaped assembly 25 is rotatably mounted to a pin 29 to enable suitable rotation thereof.
- the bottom contact rod 18 illustrated serves as a normally open circuit contact rod, connection to which being established when the wiper assembly 25 is rotated to the appropriate location.
- the conductive fibers 27 of the pultrusion 26 forming the wiper assembly are in contact with the normally closed contact 11 and the common contact 12.
- the conductive fibers 27 are brought into contact with the common contact 12 and the contact 13 of the normally open connector rod 18 to establish the electrical connection therebetween.
- the wedge or fan shaped contactor assembly 25 can be from a pultrusion formed of a body of insulating material of desired shape carrying a plurality of conductive fibers therein.
- the fibers 27 are shorted or electrically connected together within the interior of the body, and are exposed at the contact end of the wiper assembly, for example, by heat removal of the insulating portion of the pultrusion, such as by exposure to a laser beam such as an argon or carbon dioxide laser, as described above.
- FIG. 2 and 3 Another switch embodiment 30, in accordance with another embodiment of the invention, is shown in Figures 2 and 3. As shown, the switch is contained in a pair of mating cylinder or barrel assemblies 31 and 32 that may be biased against one another by a spring or other biasing means (not shown).
- One of the cylinders 31 includes a base member 33 that is rotatable on an axle 34 with respect to the other cylinder assembly 32.
- Each cylinder assembly 31 and 32 includes a pair of pultrusions 36,37 and 38,39, respectively, each formed of an insulating body in which is contained a plurality of conductive fibers, arranged along the length of the cylinder.
- the conductive fibers are arranged in a desired pattern, such as the semi-circular pattern shown in Figure 3, when viewed from an end of the cylinder, and are fibrillated at the ends of the pultrusions, so that as the cylinder assembly 31 is rotated with respect to the other cylinder assembly 32, the fibers 40,41 of the cylinder assembly 31 can be brought into and out of contact with corresponding fibers 42,43 of the other cylinder assembly 32.
- connections can be made at a distal end of the fibers to desired circuitry (not shown).
- the embodiment shown includes a pair of pultrusions each carrying respective sets of conductive fibers which are switchably interconnectable with corresponding fibers of the other cylinder.
- the fibers of one of the cylinders can be merely conductive plates or conductive portions of a substrate to serve as the contacts for selectable interconnection with the conductive fibers of the pultrusion of the other cylinder, and that various other patterns or arrangements of the pultrusions can be equally advantageously employed.
- FIG. 4-6 Another embodiment 50 of a switch in accordance with the invention is shown in Figures 4-6.
- the switch 50 employs carbon fiber pultrusions 51 and 52 as a contact mediums, and includes a disc 54 rotatably mounted on an axle 55 within a switch enclosure 58.
- the disc 54 includes a portion 59 of conducting material and a portion 60 of non-conductive material, and is attached to a lever 62 to enable the disc 54 to be rotated in the direction shown by the arrow 64.
- Two disc contacting pultrusions 51 and 52 are provided within the enclosure, each including a pultruded contact carried upon a respective conductive tube or wire 66 and 67 for connection to the circuit (not shown) to be switched.
- the pultrusion portion of the contact is formed of an insulating body in which a number of conductive fibers 68 are carried, the conductive fibers 68 being electrically connected to the bar or rod 66 upon which the pultrusion 51 is carried.
- a slot 70 is formed in the end of the pultrusion 51 to expose the conductive fibers 68 within the pultrusion 51 for contact with the disc 54.
- the slot 70 can be formed, for example, by laser beam exposure or other selective heating means to remove the insulating portion of the pultrusion matrix.
- the other pultrusion 52 can be similarly formed.
- the switch 80 includes a contact member 81 rotatably carried within a housing 82 and rotatably movable about an axle 83 by operation of a lever 85.
- a pair of conductive rods 86 and 87 are also carried within the housing 82, each conductive rod 86 and 87 having at its contact end a respective pultruded contact member 89 and 90.
- Each of the pultruded contact members 89 and 90 is formed of an insulating body 91 and 92 containing a plurality of conductive fibers 94 and 95 in electrical contact with the respective rods 86 and 87 on which they are carried.
- the ends of the contact members have been fibrillated by a laser or other heating means to remove the insulating portion of the bodies 91 and 92 of the pultruded members 89 and 90 to expose the conductive fibers 94 and 95 carried within the insulating bodies 91 and 92.
- the pultruded contact members 89 and 90 are arranged so that upon operation of the lever 85 and rotation of the rotatable contact member 81, the rotatable contact member 81 is brought into contact with the exposed fibers 94 and 95 of the pultruded contact members 91 and 92 carried on the rods 86 and 87 to close the circuit between the two.
- FIG. 8 An example of an electronic circuit in which a switch fabricated in accordance with the principles of the invention as above described is shown in Figure 8.
- a switch 100 which may include one or more elements of a carbon fiber pultrusion as described above, is shown in a series circuit between a power supply voltage and ground, including a switch biasing resistor 101.
- An active switch interface circuit 102 is connected across the resistor 101 to provide a signal on an output node, V o in accordance with the state of the switch 100, i.e., open or closed. It can be seen that the addition of an active interface circuit 102 to the carbon fiber switch 100 comprised of combinations of free and pultruded carbon fiber materials produces robust switching action, while providing a clean, predictable output response.
- a preferred embodiment of sensor 110 is shown in Figure 9.
- the embodiment of the switch 110 shown is particularly suitable for use in detecting the presence of an object, such as a sheet of paper 112 or the like passing through the switch 110.
- Such switches have widespread applications, one of which being use in electrostatographic reproducing machines or the like in which the position of a sheet,of moving paper needs to be detected or monitored as it is moved through the machine.
- the switch 110 includes a pultruded member 113 carried upon a part of the apparatus (not shown) through which the paper 112 whose presence is to be detected is moved by rollers 115 or other moving means.
- the pultruded member 113 is formed in a manner described above in detail, and includes an insulating body 116 carrying therewithin a number of conductive fibers.
- One end of the pultruded member 113 has been fibrillated by a laser (not shown) or the like to expose the contained fibers 117 for a predetermined length sufficient to traverse the path or detection zone 120 through which the paper or item to be detected is moved.
- the fibers 117 extend in their normal position to contact a conductive member 122 on the other side of the detection zone 120.
- the conductive member 122 can be either a pad of conductive material, as shown, or can be a second pultrusion fabricated in a manner similar to that of the pultruded member 113 described above.
- Electrical connections may be made to the conductive fibers 117 and to the bottom conductive member 122 to detect the continuity of the switch 120, i.e., whether it is open or closed.
- a source of potential can be applied to the bottom contact 122 via a sense resistor 125, and the conductive filaments 117 of the pultrusion 113 can be connected to a reference potential or ground.
- a current path normally exists between the source of potential, the resistor 125, the switch formed by the pultrusion 113 and the conductive pad 122 to ground, and the voltage developed thereby on the sense resistor 125 can be detected, for example by an active switch interface circuit 126 to produce a signal on an output node, V o .
- Carbon fiber switch configurations of the type described herein because of their chemical makeup and highly redundant nature, provide a means for making high reliability electrical contacts.
- the addition of the active chip level interfacing circuit 126 (Fig. 9) or 102 (Fig. 8) enables further improvements to be made in the applicability of carbon fiber switch configurations as sensors and switches.
- the interface circuit 126 or 102 shapes the waveform emanating from the fibers and provides a predictable, sharp switching response on one of two levels due to the squaring nature of its input circuitry.
- Figure 14 illustrates the output waveform of the fiber falling on the opposing contact without the active interface circuit
- Figure 15 illustrates the output waveform with the active interface circuit in place.
- the interface circuit 126 or 102 thus enables these sensors and switches to exhibit standard output responses identical with logic level devices, and provide electrically clean output waveforms which are immediately compatible with most microprocessor inputs.
- the combination with active devices allows the integration of the chip interface with the fiber switch which then provides a "stand alone" component that does not require any further signal processing. In this same vein, it is also possible to integrate more complex signal processing and detection circuitry for more sophisticated sensing devices.
- Figure 12 illustrates an exemplary functional schematic of the active interface circuit, which includes an amplifier having hysteresis.
- Figure 13 illustrates an exemplary circuit schematic employing field effect transistors (FET) and static input protection having a diode and bipolar transistor for withstanding static discharge from the passing paper.
- FET field effect transistors
- CMOS amplifier/inverter made from transistors M5 and M6.
- transistors M8-M11 form an input bias network
- transistor M12 and parallel diode together with N-well resistor form an input protection circuit.
- the output of CMOS inverter M5/M6 drives a RS flip-flop made from transistors M1-M4.
- the output of the inverter formed from transistors M3 and M4 drives output transistor M7.
- the bistable nature of the RS flip-flop gives the circuit of Figure 13 the necessary hysteresis.
- the 1K ⁇ in poly resistor and the diode between GND and VDD provide the circuit with protection from electrostatic discharge or other voltage transients on its power supply terminals.
- FIG. 10 Another sensor device embodiment 130 is shown in Figure 10 in which a conductive path is established on a single side of the sensor device 130. More particularly, a pair of contact pads 131 and 132 are provided on the bottom side of the sensor device 130, the contact pad 131 being connected to a source of potential, and the contact pad 132 being connected via a sense resistor 134 to ground.
- a pultrusion 135, carried on a frame (not shown) has conductive fibers 136 at a fibrillated end thereof that extend across the detection zone 138 to contact both of the contacts pads 131 and 132.
- the two pads 131 and 132 are spaced apart so that absent the contact by the fibers 136 of the pultrusion 135 there is no current path between the two pads 131 and 132.
- FIG. 11 Another embodiment 140 of the invention is shown in Figure 11.
- the embodiment shown is similar in operation to the embodiment described above with reference to Figure 9, and includes a pultrusion 141 that is elongated along one dimension.
- the pultrusion 141 has a plurality of electrically conductive fibers 143 carried by a host material 144, supported so that the fibers 143 extend across the detection zone 145 to contact a contact plate 146.
- a sheet of paper 148, or other item is moved through the detection zone 145, the fibers 143 are displaced, interrupting the electrical circuit and producing a voltage change on sense resistor 149.
- the pultrusion 141 and the conductive fibers are elongated essentially across the width of the detection zone 145, as shown, and therefore contact virtually the entire surface of the paper 148 as it is transported through the detection zone 145. Since the fibers 143 are connected to a reference potential, or ground, as shown, any static charge that may exist on the paper 148 is discharged as the paper traverses the detection zone 145. If desired, the fibers 143 can be connected to a reference potential other than ground so that a controlled charge can be introduced onto the paper 148 as it traverses the detection zone 145.
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- Elimination Of Static Electricity (AREA)
- Accessory Devices And Overall Control Thereof (AREA)
- Contacts (AREA)
- Manufacture Of Switches (AREA)
- Push-Button Switches (AREA)
- Paper (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US80911891A | 1991-12-18 | 1991-12-18 | |
US809118 | 1991-12-18 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0549221A1 true EP0549221A1 (fr) | 1993-06-30 |
EP0549221B1 EP0549221B1 (fr) | 1996-10-09 |
Family
ID=25200581
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19920311374 Expired - Lifetime EP0549221B1 (fr) | 1991-12-18 | 1992-12-14 | Commutateurs et capteurs utilisant des contacts obtenus par pultrusion |
Country Status (4)
Country | Link |
---|---|
US (1) | US5420465A (fr) |
EP (1) | EP0549221B1 (fr) |
JP (1) | JP3342906B2 (fr) |
DE (1) | DE69214414T2 (fr) |
Families Citing this family (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5794100A (en) * | 1997-03-25 | 1998-08-11 | Xerox Corporation | Carbon fiber electrical contact for rotating elements |
US5812908A (en) * | 1997-03-25 | 1998-09-22 | Xerox Corporation | Carbon fiber electrical contact mounting for rotating elements |
US5887225A (en) * | 1998-01-05 | 1999-03-23 | Xerox Corporation | Solid carbon fiber electrical rod developer bias contacting method |
US6246012B1 (en) | 1999-03-24 | 2001-06-12 | Xerox Corporation | Electroplated conductive carbon fibers with adhesive |
US6444102B1 (en) | 2000-02-07 | 2002-09-03 | Micro Contacts Inc. | Carbon fiber electrical contacts |
US8029296B2 (en) * | 2000-02-07 | 2011-10-04 | Micro Contacts, Inc. | Carbon fiber electrical contacts formed of composite carbon fiber material |
US8398413B2 (en) | 2000-02-07 | 2013-03-19 | Micro Contacts, Inc. | Carbon fiber electrical contacts formed of composite material including plural carbon fiber elements bonded together in low-resistance synthetic resin |
US6852395B2 (en) | 2002-01-08 | 2005-02-08 | North Carolina State University | Methods and systems for selectively connecting and disconnecting conductors in a fabric |
US20040000985A1 (en) * | 2002-06-26 | 2004-01-01 | Alps Electric Co., Ltd. | Sliding-type electric component including carbon fiber contact |
WO2004003273A2 (fr) * | 2002-06-28 | 2004-01-08 | North Carolina State University | Structures de tissus et de fils pour ameliorer l'integrite du signal dans des circuits electriques a base de tissus |
FR2858133B1 (fr) * | 2003-07-25 | 2006-02-03 | Michel Combier | Dispositif de commutation electrique intelligent pour la securisation des moyens de distribution d'electricite |
US7052763B2 (en) * | 2003-08-05 | 2006-05-30 | Xerox Corporation | Multi-element connector |
US20050031840A1 (en) * | 2003-08-05 | 2005-02-10 | Xerox Corporation | RF connector |
US7266322B2 (en) * | 2005-03-31 | 2007-09-04 | Xerox Corporation | Multi-functional electro-mechanical interconnect, sensor, and mounting and method of mounting and biasing of a rotatable member |
US8721850B2 (en) * | 2010-02-02 | 2014-05-13 | Roche Diagnostics Operations, Inc. | Biosensor and methods for manufacturing |
US20150195897A1 (en) | 2014-01-08 | 2015-07-09 | Joseph A. Swift | Apparatus having management of electrical power capacity regions and management of thermal capacity regions |
WO2016033328A1 (fr) | 2014-08-27 | 2016-03-03 | North Carolina State University | Codage binaire de capteurs dans des structures textiles |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0180378A2 (fr) * | 1984-10-29 | 1986-05-07 | Xerox Corporation | Charge à brosse par contact |
US4641949A (en) * | 1985-08-26 | 1987-02-10 | Xerox Corporation | Conductive brush paper position sensor |
EP0369772A2 (fr) * | 1988-11-17 | 1990-05-23 | Xerox Corporation | Dispositif de conduction du courant électrique |
EP0370818A2 (fr) * | 1988-11-25 | 1990-05-30 | Xerox Corporation | Connexion électrique à deux éléments |
Family Cites Families (18)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3568145A (en) * | 1968-01-19 | 1971-03-02 | Joseph K Dikoff | Tire-warning apparatus |
US3985981A (en) * | 1975-03-26 | 1976-10-12 | Gulf & Western Manufacturing Company (Hastings) | Program switch assembly having adjustable contact structure |
US4358699A (en) * | 1980-06-05 | 1982-11-09 | The University Of Virginia Alumni Patents Foundation | Versatile electrical fiber brush and method of making |
US4336565A (en) * | 1980-08-04 | 1982-06-22 | Xerox Corporation | Charge process with a carbon fiber brush electrode |
EP0105639B1 (fr) * | 1982-09-08 | 1988-01-07 | Kabushiki Kaisha Toshiba | Production d'une résistance à partir de matériau isolant par chauffage local |
JPS60167491A (ja) * | 1984-02-10 | 1985-08-30 | 株式会社東芝 | 導体路形成方法 |
US4761709A (en) * | 1984-10-29 | 1988-08-02 | Xerox Corporation | Contact brush charging |
JPH0712111B2 (ja) * | 1985-09-04 | 1995-02-08 | ユーエフイー・インコーポレイテッド | 電気回路埋設方法及びプラスチック製品 |
US4894500A (en) * | 1987-12-01 | 1990-01-16 | Copal Electronics Co., Ltd. | Rotary selector switch |
US4967314A (en) * | 1988-03-28 | 1990-10-30 | Prime Computer Inc. | Circuit board construction |
US4841099A (en) * | 1988-05-02 | 1989-06-20 | Xerox Corporation | Electrically insulating polymer matrix with conductive path formed in situ |
JP2841461B2 (ja) * | 1989-04-26 | 1998-12-24 | 富士ゼロックス株式会社 | 静電搬送転写装置及び、該装置に用いる樹脂膜ベルトの製造方法 |
JP2864533B2 (ja) * | 1989-05-24 | 1999-03-03 | 富士ゼロックス株式会社 | 画像形成装置 |
DE69024113T2 (de) * | 1989-07-05 | 1996-07-11 | Yugen Kaisha Ohta Kogyo Kohfu | Farbroller und Verfahren, das diesen Roller verwendet |
US5139862A (en) * | 1989-11-17 | 1992-08-18 | Xerox Corporation | Pultruded electronic device |
JPH03219509A (ja) * | 1989-11-25 | 1991-09-26 | Seiko Epson Corp | スイッチ基板及びスイッチ基板製造方法 |
US4970553A (en) * | 1989-12-04 | 1990-11-13 | Xerox Corporation | Electrical component with conductive path |
CA2037801C (fr) * | 1990-04-16 | 2001-04-24 | Thomas E. Orlowski | Composant electrique fibrille et pultruse |
-
1992
- 1992-12-10 JP JP35252792A patent/JP3342906B2/ja not_active Expired - Fee Related
- 1992-12-14 DE DE69214414T patent/DE69214414T2/de not_active Expired - Lifetime
- 1992-12-14 EP EP19920311374 patent/EP0549221B1/fr not_active Expired - Lifetime
-
1994
- 1994-08-30 US US08/297,734 patent/US5420465A/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0180378A2 (fr) * | 1984-10-29 | 1986-05-07 | Xerox Corporation | Charge à brosse par contact |
US4641949A (en) * | 1985-08-26 | 1987-02-10 | Xerox Corporation | Conductive brush paper position sensor |
EP0369772A2 (fr) * | 1988-11-17 | 1990-05-23 | Xerox Corporation | Dispositif de conduction du courant électrique |
EP0370818A2 (fr) * | 1988-11-25 | 1990-05-30 | Xerox Corporation | Connexion électrique à deux éléments |
Also Published As
Publication number | Publication date |
---|---|
JPH05298952A (ja) | 1993-11-12 |
DE69214414D1 (de) | 1996-11-14 |
JP3342906B2 (ja) | 2002-11-11 |
EP0549221B1 (fr) | 1996-10-09 |
US5420465A (en) | 1995-05-30 |
DE69214414T2 (de) | 1997-03-13 |
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